Here's the first draft of the how to run a film night thing. Change, discuss, drool...
How to run a film night.

Films are fun. And important. So important, you've got to make sure everyone's getting a 120% cinematic experience. This is where you come in, oh Grand Master/Mistress of Cinematique-ah!Here's a few things you may want to do.

1. About half an hour before the film is about to start you may want to tell everyone there is going to be a film shown soon, and what we expect to happen.

“In half an hour there is going to be a showing of [Legally Blond 2] here on the big screen. All are welcome, but please feel free to move next door if you don't want to watch the film. Films are fun. Gasbags are not.”

Or something along those lines.

2. Do the same with 10 mins to go, and suggest people start moving now. Stick on some popcorn. I suggest a bit of oil and loads of weird spices. Cinnamon, black pepper and sugar.

3. Dim the lights, shut the shutters etc. Get the film ready. When about to press play announce that it is about to start, if people just want to chat move next door, please be quiet while the film is on, respect the other people who are here to enjoy this masterpiece.

4. If you notice people being annoying during a film go up and say. You're perfectly within your right, and we have all agreed on this. Just say people are enjoying the film, if you want to chat move next door.

Or give them this [we will print these off]...

A short lesson on basic social ettiquiette.Hello person. You are a gasbag. We find it very embarrassing to have to train you how to be polite and respectful, but YOU ARE TALKING while other people are trying to BE ATTENTIVE TO THE FILM. Please move next door if you want to chat. If you keep talking we will ask you to leave.In case you need help in other social circumstances, let us remind you never to place your elbows on the table during meals, bow or curtsey should you ever meet the queen, and if a gay man wears a blue and white striped hankerchief in his left pocket he is a sailor, but it it's in his right pocket it means he's looking for salty seamen.

5. Enjoy the film, have a great time, and be proud you were the one on the battlefeild, fighting for cinematic justice while all others fell silent and weak. Hurrah!